Some Further Results of J-Integral Analysis and Estimates

It is shown that the J-integral can be directly evaluated from single load-displacement records for a series of crack toughness specimens having the common feature that their only significant length dimension is that of the uncracked ligament. For the special case of bending loads on the ligament of a deeply cracked bar, J is shown to be twice the work of deformation divided by the ligament area. This and like results are employed to discuss Charpy and “equivalent energy” toughness measures and also to evolve yet simpler estimating procedures for the J-integral.